Microelectrode studies are being conducted in the vestibular nerve and vestibular nuclei of the squirrel monkey (Saimiri sciureus). The goal of the project is the elucidation of the various peripheral endorgans in primates and of the ways in which information encoded peripherally is transformed in central pathways. Specific research goals for the coming year are: 1) An attempt will be made to identify the distinctive physiology of the thick and thin peripheral axons innervating, respectively, Type-I and Type-II hair cells. 2) A study will be begun of the peripheral action of vestibular efferents. 3) Work will continue on the organization of the MVN. BIBLIOGRAPHIC REFERENCES: Goldberg, J. M. and Fernandez, C. Vestibular mechanisms. Ann. Rev. Physiol. 37:129-162, 1975. Goldberg, J. M. and Fernandez, C. Response of peripheral vestibular neurons to angular and linear accelerations in the squirrel monkey. Acta Otolaryng. 80:101-110 1975.